| | Millville, NJ | Smithsburg, MD | United States |
| Population | 27,946 | 2,986 | 329,725,481 |
| Female Population | 52.4% | 53.3% | 50.5% |
| Male Population | 47.6% | 46.8% | 49.5% |
| Median Age | 44.3 | 35.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 28,497 | 2,995 | 309,327,143 |
| Population - 2000 | 26,847 | 2,146 | 285,036,114 |
| Population - 1990 | 25,992 | 1,221 | 251,960,433 |
| Pop. 2000 to Now | 0.7% | 38.4% | 15.6% |
| Pop. 1990 to Now | 4.0% | 143.2% | 30.8% |
| space4 | | | |
| Population Density | 665.4 | 2,862.9 | 93.4 |
| Land Area | 42.0 | 1.0 | 3,531,905.4 |
| Water Area | 2.5 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Millville, NJ | Smithsburg, MD | United States |
| Age 0 to 4 | 4.7% | 4.9% | 5.9% |
| Age 5 to 9 | 5.7% | 7.5% | 6.1% |
| Age 10 to 14 | 7.7% | 11.0% | 6.6% |
| Age 15 to 17 | 3.1% | 6.7% | 3.9% |
| Age 18 to 20 | 3.4% | 4.6% | 4.0% |
| Age 21 to 24 | 4.6% | 3.2% | 5.2% |
| Age 25 to 34 | 11.2% | 10.9% | 13.8% |
| Age 35 to 44 | 10.4% | 12.1% | 12.9% |
| Age 45 to 54 | 17.7% | 15.5% | 12.6% |
| Age 55 to 59 | 7.3% | 8.4% | 6.7% |
| Age 60 to 64 | 6.3% | 5.7% | 6.3% |
| Age 65 to 74 | 11.1% | 6.4% | 9.6% |
| Age 75 to 84 | 5.2% | 3.0% | 4.5% |
| Age 85 and over | 1.6% | 0.1% | 1.9% |
| space1 | | | |
| Race | | | |
| | Millville, NJ | Smithsburg, MD | United States |
| White | 58.4% | 90.3% | 59.4% |
| Black | 15.4% | 3.5% | 12.2% |
| Asian | 2.4% | 3.5% | 5.6% |
| Native American | 0.1% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.3% | 0.0% | 0.4% |
| Two or More Races | 5.7% | 1.6% | 3.2% |
| Hispanic | 17.8% | 1.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Millville, NJ | Smithsburg, MD | United States |
| Married Population | 46.3% | 60.2% | 49.8% |
| Currently Married | 43.6% | 58.8% | 48.0% |
| Married but Separated | 2.7% | 1.4% | 1.8% |
| Single Population | 53.7% | 39.8% | 50.2% |
| Never Married | 35.3% | 25.6% | 33.8% |
| Divorced | 11.1% | 9.4% | 10.8% |
| Widowed | 7.3% | 4.8% | 5.6% |
| space5 | | | |
| Household Size | 2.33 | 3.01 | 2.60 |
| Households | 11,887 | 993 | 124,010,992 |
| Family Households | 7,212 | 810 | 80,755,759 |
| Married couple, w/children | 22.4% | 34.9% | 30.5% |
| Married couple, no children | 42.7% | 40.6% | 42.9% |
| Non Family Households | 4,675 | 183 | 43,255,233 |
| Single householder, w/children | 21.4% | 15.3% | 15.8% |
| Single householder, no children | 13.5% | 9.1% | 10.8% |